Background creation of conf. class &1 (type: &2) failed; error code &3

What causes this issue?

The system tried to create or modify the configuration class &V1& for
class type &V2& and has detected an inconsistency which has led to error
code &V3&. This error occurred during the ALE inbound processing of a
CLSMAS IDoc. This situation can occur while processing merchandise
categories or characteristic profiles (classes belonging to class type
026) via CLSMAS IDoc.


Functional Background
To create a generic article in SAP ERP, you usually assign
variant-creating characteristics to either a merchandise category or a
characteristics profile. In SAP S/4HANA, the characteristics assigned to
a configuration class are used to create generic articles.
If an SAP ERP system distributes article-related classification master
data to an SAP S/4HANA system, the classification master data is
enriched during inbound processing in such a way that the configuration
classes required can be created automatically with the relevant
variant-creating characteristics assigned to them.
If generic articles are to be distributed from SAP ERP to SAP S/4HANA
and if the required configuration classes are not to be created in
advance in the expected way, an error would occur during inbound
processing of the ARTMAS IDocs for the generic articles. To prevent this
situation, the missing classification/configuration master data in the
receiving SAP S/4HANA system is maintained automatically when the
classification data has been distributed from an SAP ERP system using
Application Link Enabling (ALE) technology.
The data is enriched in the following ways:
If a new characteristics profile with variant-creating characteristics
is processed within the CLSMAS inbound, a new configuration class with
the same name is created. The variant-creating characteristics used in
the characteristics profile are applied to the corresponding
configuration class.
If any changes are made later with regard to the characteristics
profile, these changes are applied to the corresponding configuration
class.
If the variant-creating characteristics are assigned to the merchandise
category instead of using characteristics profiles and if a new
merchandise category is processed within the CLSMAS inbound, the system
searches for an existing configuration class that provides the same set
of variant-creating characteristics. If there is no match, a new
configuration class with a generated class name is created. The
variant-creating characteristics used in the merchandise category are
applied to the corresponding configuration class.
If any changes are made later with regard to the merchandise category,
these changes are not applied to one of the matching configuration
classes because such a configuration class could be shared by several
merchandise categories. The systems checks whether the current
variant-creating characteristics are appropriate and, if there is no
match, it creates a new configuration class.
The creation of a new configuration class in SAP S/4HANA ensures that if
additional variant-creating characteristics are assigned to a
merchandise category in SAP ERP that is not used by any article, the
variant-creating characteristics are assigned to an appropriate
configuration class after distribution to SAP S/4HANA.
Later on, when the ARTMAS IDoc of a generic article is processed in the
receiving system and the IDoc does not provide a configuration class,
the system tries to find a suitable existing configuration class based
on the variant-creating characteristics specified in the ARTMAS IDoc. If
a generic article is assigned to a characteristics profile, a
configuration class with the same name is expected to exist. If a
generic article is assigned to a merchandise category, the first found
configuration class that provides the right variant-creating
characteristics is used.
To ensure that the classification master data meets specific
requirements, checks are performed during the CLSMAS IDoc inbound
processing of merchandise categories and characteristics profiles. If
the requirements are not met, the following error codes are issued:
Error code 1: No suitable class type could be found for the creation of
the new configuration class. The needed class type has to be customized
to support variant configuration. In general class type 300 provides
this required setup (TCLA-VARKLART = "X").
Error code 2: Data mismatch between the class data provided via the
corresponding interface tables and the class currently processed. This
situation shouldn't happen in general.
Error code 3: The search for an already existing configuration class
when processing a characteristics profile recognizes an inconsistency.
If the characteristics profile doesn't exist in the receiving SAP
S/4HANA the corresponding configuration class with the same class name
also must not exist. If the characteristics profile already exists, also
the corresponding configuration class has to exist.
Error code 4: The retrieval of a new internal class number (KLAH-CLINT)
out of the defined number range failed for the new configuration class.

System Response

To avoid any inconsistencies or follow-up issues, the system stops
processing the related CLSMAS IDoc. The relevant merchandise category or
characteristics profile is not created as a class of class type 026 in
the receiving SAP S/4HANA system.

How to fix this error?

Check which data related to the characteristics profile or merchandise
category is causing the error and, depending on the error code, do the
following:
Error code 1: Check the customizing setup of your class types, at least
one class type has to support a variant configuration scenario
(TCLA-VARKLART = "X").
Error code 2: This error situation indicates a severe system problem and
must be reported to SAP as an incident.
Error code 3:
If the corresponding characteristics profile still does not exist in the
receiving SAP S/4HANA system (check by using transaction CLWG) and a
configuration class with the same name exists (check by using
transaction CL03), try to delete this configuration class if it is not
being used and restart the CLSMAS IDoc inbound processing.
If the configuration class is being used and it is not possible to
delete it, create another characteristics profile in your SAP ERP system
with a different name to prevent the name collision. We recommend that
you use a specific prefix for configuration class names if you need to
create configuration classes locally in the receiving SAP S/4HANA
system.
If the corresponding characteristics profile already exists in the
receiving SAP S/4HANA system (check by using transaction CLWG) but the
related configuration class is missing, create the configuration class
manually (by using transaction CL01) and assign the necessary
characteristics (based on the variant-creating characteristics of the
characteristics profile) to the configuration class; then restart CLSMAS
IDoc inbound processing.
Error code 4: Check your number range setup (transaction SNUM with
object KLASSE).
It might be possible that the last number out of the range has been
fetched and a cleanup has to be done or that a number that is already
used has been retrieved by mistake.
Check the last provided class number against the class numbers used in
database table KLAH (field CLINT) to find a potential overlap. If
possible, increase your number range counter to a value greater than the
highest used KLAH-CLINT value.

Procedure for System Administrators

If you are not planning to supply an SAP S/4HANA system with
classification and generic article master data out of an SAP ERP system
or a compatible legacy system, you can switch off this functional
enhancement to prevent the creation/change of configuration classes when
a CLSMAS IDoc is processed for a merchandise category or characteristics
profile.
In an ALE distribution scenario with two SAP S/4HANA systems, we
recommend that you switch off this function in the receiving system.
If this function is enabled, unnecessary configuration classes might be
created when you transfer merchandise categories or characteristics
profiles. However, these unused configuration classes can be deleted
afterwards by using transaction CL04 if necessary.
By default, this function is enabled to support the automatic creation
of configuration classes and to meet compatibility requirements. If you
initially switch off this function, but need to enable it later, you
must recreate the missing configuration classes manually by using
transaction CL01 as described for error code 3.
You can switch off this function in Customizing for <LS>Logistics -
General</> under <LS>Material Master -> Retail-Specific Settings ->
Settings for Hybrid ALE Scenarios (SAP ERP-SAP S/4HANA) -> Deactivate
Automatic Creation of Configuration Classes</>.

Error message extract from SAP system. Copyright SAP SE.